Propagation of trees from cuttings



Patented Jan. 9, 1934 UNITED STATES PATENT QFFICE No Drawing. Aplication August 2, 1932 Serial No. 627,304

10 Claims.

This invention relates to an improvement in methods of propagating treesfrom cuttings.

The principal object of this invention is to increase the number ofliving trees obtainable from a given number of tree cuttings.

An important object of the invention is to prolong the periods when treecuttings may be taken and set out successfully.

, A further object of the invention is to promote the growth of treecuttings taken or set out under conditions which normally do not permitgrowth to occur.

Other objects and advantages of the invention will-become apparentduring the course of the following description.

-As is well known, one of the customary ways of propagating trees is bytaking a cutting", sometimes called a scion or slip, from a living treeand inserting the lower portion of such cutting in the ground.Ordinarily, cuttings are made from wood which has grown one summer andthen hardened in the fall. Wood that is more than two years old usuallydoes not grow when planted as a cutting. The highest percentage ofgrowth is obtained by planting in the spring the cuttings from wood ofthe preceding summers growth. In securing the cuttings it is customaryto wait until after the leaves have fallen from a tree and then branchesof about one-fourth inch or larger diameter are out out into lengths ofabout fourteen inches. This is usually carried out in the fall, sayNovember or December, and the cuttings stored in a cool, damp place, asin an icehouse orin the ground below the frost line, until spring.During this period callouses are formed. These callouses are in thenature of wart-like growth over the ends of the cutting. When the groundhas warmed up in the spring, say in March or April, depending upon thelocality, the cuttings are planted with about six inches of the cuttingsabove ground. It is ordinarilyundersto'od by those experienced inarboriculture that mature, hardened cuttings (taken after frost andafter leaves have fallen) with callouses, are necessary toget a highpercentage of the cuttings to grow.

,While cuttings are usually calloused before planting, in certain cases,as with more vigorous trees such-as willows, a certain measure ofsuccess can be obtained by the use of uncalloused cuttings if they arehardened,. of full size, and

planted under favorable conditions. However, I am not aware of any casein which green cuttings or small cuttings (about one-eighth inchdiameter and four to six inches long) have been use of green woodcuttings.

successfully grown, whether calloused or uncalloused, under out-of-doorconditions.

As stated above, it is the generalpractice in propagating trees fromcuttings to use only wood of one summers growth. Wood which is in themactive growing stage is known as green wood from the color of the barkof most of such wood, which is sometimes also known as soft wood.

It is well known that growth from cuttings made from green wood, thatis, green wood cuttings, is exceedingly difficult, and in manyl casesim: possible, to obtain even under the best conditions. Accordingly, noattempt is made in the commercial propagation of trees from cuttings tomake As a matter of fact, even when hardened wood cuttings are used andthe cuttings set out under favorable conditions, the percentage ofgrowth of the cuttings leaves much to be desired. As an illustration ofthe difficulties of propagation by cuttings under the methods commonlyknown in arboriculture, in the spring some years ago one of the papercompanies in this country planted near the shore of Lake Champlain about500,000 calloused cuttings of the ordinary poplar wood used for papermaking (Populus tremuloides) in a nursery. Although the work was doneunder the direction of an experienced forester, only about one per cent.of the cuttings rooted. In other words, over 99 per cent. of thecuttings died before growth started.

In connection with my study of the practical 1 side of tree propagation,and particularly in my experimental work in the propagation of thehybrid poplars described in my copending application Serial No. 477,979,filed August 26, 1930, I concluded that in order to put'the commercialpropagation of trees on a practical and economic basis it would benecessary to develop some means for securing a greater yield of livingtrees from a given source of cuttings. As a result of extensiveexperimental work directed to this problem I have developed animprovement in the method of propagating trees from cuttings whichovercomes the disadvantages mentioned above 100 and also results incertain new advantages.

I have found that if cuttings are treated to provide a waterproofcoating on the upper portion thereof, say approximately the upper half,and the cuttings are otherwise handled in ac- 105 cordance with theusual methods referred to above, a materially higher percentage of thecuttings will grow and produce living trees than if the cuttings werenot so treated. Certain of my experimental work has been with some seven10 green wood the leaves are varieties of trees which would ordinarilygrow from large mature cuttings planted in the spring to the extent ofabout 70 per cent. of the cuttings planted. By treating the cuttngs inaccordance with the present invention I found that cuttings of but halfthe usual length and very much smaller diameter could be used. Thismeans that whereas by the former methods the growth of one summer fromone cutting would under the best circumstances give six to eightcuttings, say seven on an average, useful for the next year, under thepresent method similar growth will yield thirty cuttings and a materially higher percentage of living trees.

In my experimental work I have taken as controls small cuttings, even assmall as one-eighth inch in diameter and four inches long. When thesewere planted without being previously treated in accordance with thepresent invention, the cuttings being planted under favorable conditionswith about three inches under ground and one inch above ground,practically all died whether they were hardened cuttings taken in thefall or green wood cuttings taken in June or and approximately the upperhalf coated by dipping into molten parafiin, and then planted in thesoil, the major proportion of even those small cuttings grew and formedtrees. With larger cuttings, say of one-fourth inch diameter andpreferably six inches long, growth occurred in between and 90 per cent.of the cuttings used. Moreover, when treated in accordance with thepresent invention there seems to be no advantage of hardened wood overgrowing green wood. Of course, when cuttings are taken from growingpreferably out off and only the stem planted.

r A second advantage, and a most important one from a commercialstandpoint, is that whereas by .the former methods of propagation it isnecessary to do the planting in a few weeks in the spring just after thefrost is out of the ground or, less advantageously, in a few weeks justbefore the ground freezes in the fall, say two or three weeks at eachperiod, it is possible by my new method to do the planting at theplanters convenience during the entire growing season, that is, to takeoff branches from growingtrees, make cuttings of the desired length,waterproof a portion of each cutting and plant themall on the same halfday and at any convenient time. This is exceedingly important from thecommercial side as it lengthens the planting season and does away withthe rush when one is planting any large acreage. To plant a thousandacres,

which is not a large forestry plantation, requires about one andone-fourth million trees on the basis of the trees being set about sixfeet apart, the customary distance. It is almost impossible to gather asufficient number of men locally to plant these cuttings in the two orthree weeks in which it should be donein the spring. By my new method, asmall crew can be used continuously from March to November, that is, aslong as the ground is not frozen, for this purpose.

Another advantage ofmy present process which permits the use of greencuttings is that the trees can be pruned at a convenient time, as duringthe summer, and the prunings planted at once so that new areas can bereforested and at the same time the areas already planted improved bypruning. Thus, the prunings aresaved and used, whereas by the oldmethod, they are discarded.

As stated above, I prefer to treat the cuttings, whether from green orhardened wood, by coating approximately the upper half of the cuttingswith a waterproofing material. This .is generally done when the cuttingsare taken, particularly in the case of green wood cuttings. While Iprefer to provide the waterproof coating on the cuttings by dipping theminmolten paraffin, other materials may be substituted for the paraflinand other methods of applying the waterproof coatings may be employed.For example, beeswax, cellulose nitrate lacquers, cellulose acetatelacquers and the like may be used. However,

vent. For example, instead of molten paraflin,

parafiin dissolved in a solvent such as toluene may be used. Numerousother materials will occur to those skilled in the art. As a matter offact, any material is suitable which will give' a waterproof coating andat the same time will permit the expanding buds later to break throughthe coating.

I have found that this improvement in tree propagation is particularlyadapted to the propagation of members of the poplar family, notablyhybrid poplars, from cuttings. Especially have I found that thefollowing numbered hybrid varieties obtained by crossing the species ofthe genus populus set forth below and which are described in mycopending application Serial No.

477,979, filed August 26, 1930, may advantageously be propagated by mynew method described above:

Variety 1. alba adenopoda 2. alba ireinnla Davidiana 3. alba balsnmifernVirginians 4. angulata caudinn 5. nngulata eugenei 6. angulataplantiercnsis 7. angulata rolmsta 8. angulata trichncarpa 9. balsamifcravirginiana herolinicnsis 10. hnlsamiferu Virginians. caudina l1.balsamifera virginiana eugenvi 12. balsamifera virginiana incl'nssata13. balsamifera Virginians. planticrensis 1%. halsamiifera virginiannrobusta 1:). balsamiiem virginiana (male) trichocarpa (female) 16. n graadenopoda 17. nigra beroliniensis rosslca 18. n gra eugenei- 19. nigranigra italica 20. nigra charkowiensis balsamifera vlrginiana 21. n gracharkowiensis caudina 22. mgr-a charkowiensis incrassata 23. nigrnchgirkowiensis plantierensis 24. Snrgentn I beroliniensis rossica 25.Sargentil 'monii 26. mgr-:1 laurlfolia 27. nigra baat'nnicorum vitrumtrichocarpu 28. n gra betulafolia balsamifera virglniana 29. mgrncharkowiensis cugenei 30. nngulata grandiolenta I 31. angulataincrassata 32. Fremontii balsamifera virginiana 33. nigra clmrkowiensisrobusta 34. argentii nigra ltalicn 35. Simonii beroliniensis 36 Simoniirobustu All of the members of this general class of hybrid poplars whichI have developed may advantageously be propagated in the mannerdescribed. However, I particularly recommend for is not intended toinclude a cutting or scion used in grafting, i. e. where the cutting orscion is inserted into another piece of wood or vine and the two growtogether and become one.

While I have described in detail the preferred embodiment of myinvention it is to be understood that the details of procedure may bevariously modified without departing from the spirit of the invention orthe scope of the subjoined claims.

I claim:

1. The method of propagating trees from cuttings which are taken or setout under conditions which normally tend to prevent growth whichcomprises providing a waterproof coating on the upper portion of saidcuttings, and planting the thus treated cuttings.

2. The method of propagating trees from cuttings which are taken or setout under conditions which normally tend to prevent growth whichcomprises providing a coating of paraffin on approximately the upperhalf of said cuttings when said cuttings are taken, and planting thethus treated cuttings.

3. The method of propagating trees from cuttings taken from green woodwhich comprises coating approximately the upper half of said cuttingswith waterproofing material when said cuttings are taken, and plantingthe thus treated cuttings.

4. The method of propagating trees from cuttings taken from green woodwhich comprises removing the leaves from said cuttings and coatingapproximately the upper half of said cuttings with paraflin when saidcuttings are taken, and

can safely be set out and by permitting the use of relatively shortcuttings and cuttings of relatively small diameter which comprisesapplying a waterproofing material to the upper portion of said cuttingsprior to planting the same. I

6. In the propagation of trees by plantin cuttings taken from the treesto be propagated, the method of increasing the number of living treesobtainable from a given source of cuttings by prolongingthe times withinwhich cuttings can safely be set out and by permitting the use ofrelatively short cuttings and cuttings of relatively small diameterwhich comprises coating approximately the upper half of said cuttingswith a waterproofing material when said cuttings are taken.

7. In a method of propagating trees, wherein cuttings are taken from thetrees to be propagated and such cuttings are planted in-soil, theimprovement which comprises applying a waterproofing material to theupper portion of said cuttings prior to planting the same.

8. In a method of propagating trees, wherein cuttings are taken from thetrees to be propagated and such cuttings are planted in soil, theimprovement which comprises coating approximately the upper half of saidcuttings with a waterproofing material when said cuttings are taken.

9. In a method of propagating trees of the poplar family whereincuttings are taken from the poplars to be propagated and such cuttingsare planted in soil, the improvement which comprises coating:approximately the upper half of said cuttings with a waterproofingmaterial prior to planting the same.

10. In a method of propagating hybrid poplars, wherein cuttings aretaken from the hybrid poplars to be propagated and such cuttings are,planted in soil, the improvement which comprises providing a coating ofwaterproofing ma-'

